The present invention relates to protocol testing, and more particularly to performing and implementing a test task relating to a specific protocol layer of a protocol stack in an apparatus to be tested.
The field of protocol testing is a highly innovative one. After each improvement or new development of telecommunication and network protocols, manufacturers and operators of telecommunication and network apparatuses face a problem of function and conformance testing new plants. For competition reasons the manufacturers are anxious to launch their products into the market as early as possible. The high pace of these developments places special demands on the manufacturers of protocol systems. To keep test times for the new plants as short as possible and to burden test personnel with as little protocol knowledge as possible, the manufacturers often use protocol emulations on protocol test systems. In actual practice emulations of a protocol are frequently prepared by having each of the emulations reproduce individual protocol layers. In this way it is possible to reproduce entire protocol stacks or selected parts of a protocol stack by joining the individual protocol layers to form an emulation system. The individual protocol layers are viewed abstractly and in this way pass on data from layer to layer. Specifications of protocols usually use so-called primitives to describe the communication between the protocol layers. In this connection reference is made to the ISO OSI (International Standard Organization's Open System Interconnect) reference model, which is hereby incorporated by reference.
FIG. 1 shows for clarification the bottom part of a protocol stack with emulation layers E1, E2 and E3 where the bottom-most emulation layer E1 is connected to a physical layer PL. To test a certain protocol layer according to the prior art (FIG. 2), the relevant emulation layer is newly programmed with respect to the new test task. In FIG. 2 the second layer therefore is replaced by a test layer TL to test emulation layer E2. This involves a considerable programming effort, because the entire procedural sequence of the relevant protocol layer has to be intercepted in the test layer, which is reflected in a correspondingly high implementation and maintenance effort. This programming effort must be repeated to test another layer of the protocol stack. In the prior art the test layer has to be programmed such that on the one hand it fulfils the task and on the other it also exhibits all functionalities exhibited by the emulation layer E2. Moreover for each new measurement task of the relevant protocol layer, the test layer TL needs to be reprogrammed accordingly. In the case of the test layer TL the programming of the emulation layer is therefore not distinguished sufficiently from the programming of the measurement task—both parts are rather more intertwined in respect of simple, clear programming. Yet separate programming of the two parts in the prior art is not required because the test layer replaces the relevant emulation layer regardless of the type of programming. What is essential in the prior art is that the test layer realizes both basic functions, i.e., the functions of the emulation layer and the functions of the measurement task.
For further details on the prior art reference is made as follows:                From U.S. Published patent application No. 20030172342 there is shown a system and method that identifies the limits of an Upper Layer Protocol (ULP). However it does not relate to the message flow and interactions with other components.        From U.S. Published patent application No. 20030086536 there is shown a method for testing one or several OSSs (Operations Support Systems) of an ILEC (Incumbent Local Exchange Carrier). In this connection several actions are performed which, with the implementation of a test schedule, serve to test one or several ILEC OSS elements.        From U.S. Published patent application No. 20030014611 there is shown a development tool that supports the implementation of software for a DSP (Digital Signal Processor). A similar disclosure can be found in U.S. Published patent application No. 20030004697.        In U.S. Published patent application No. 20020191543 parameters are identified in a packet of data flows to test whether the relevant parameter value complies with specific requirements. However the discussion is limited to the bandwidth aspect and hence isolated from the message flow itself.        U.S. Published patent application No. 20020162059 deals with a test system for communication networks which allows autonomous or user-free interaction between the administrative interfaces of different network appliances to be tested. The test system has appliance-specific packets for communication interfaces, which serve to convert general commands into appliance-specific commands.        U.S. Pat. No. 6,661,780 provides mechanisms for mapping rules concerning the QoS (Quality of Service) in a mobile network between a UMTS (Universal Mobile Telecommunications System) layer and an IP (Internet Protocol) layer.        U.S. Pat. No. 6,512,988 relates to a test management system that may be used for processing test cases. However it does not describe implementation methods of test cases.        From U.S. Pat. No. 6,363,053 there is known a method for testing the QoS of a network. It involves the use of the classic approach in which a test component simulates or emulates a node element.        
What is desired is to further develop a generic protocol tester or a generic method such that much lower work and time effort is required for the programmer in preparing a test case.